While attuned to the Ring of the Aetherlord, and under the tutelage of Eldrin of Thulanthor, you unlock a deeper understanding of the powers of the ring.

Once per day, when you are reduced to zero hit points while attuned the Ring of the Aetherlord you can cast the Ghost Form spell as a reaction, leaving your body in stable condition (but still unconscious and at zero hit points. You are now able to cast the Ghost Form as a 6th level spell.

You also gain access to the Aether Weapon spell as a 4th level spell, and can cast it at will as a free action.

Should you lose attunement to the ring, you lose access to this Feat.